Field of the Invention
The present invention relates to a control apparatus and a control method of the same.
Description of the Related Art
As the printing speed and printing resolution of an inkjet printing apparatus (to be referred to as a printing apparatus hereinafter) improve in recent years, the number of nozzles for discharging ink is increasing. When forming an image by using the printing apparatus like this, the power consumption changes in accordance with the density of an image. For example, when forming a high-density image by discharging a large amount of ink onto the paper surface by using a thermal method, a large number of heaters arranged near the ink discharge ports of nozzles are instantaneously turned on, so a large current flows within a short time period.
When designing a power supply which supplies a large instantaneous current, the impedance of the power supply must generally be decreased. As one means for a printer, a method of connecting an electrolyte capacitor to a power supply line near a printhead is known. Since charge stored in the electrolyte capacitor is supplied as instantaneous electric power, it is possible to prevent a heat driving voltage drop and implement stable ink discharge even in a situation in which a large current instantaneously flows. Recently, the capacitance of this electrolyte capacitor must be increased for a head in which the number of nozzles has increased. In addition, the supply power of the power supply itself must be increased in accordance with the increase in number of nozzles.
On the other hand, to shorten the processing time of the printing apparatus, it is necessary to shorten the time of each of charging and discharge of a large-capacitance electrolyte capacitor, and currents flowing through a charging circuit and discharge circuit tend to increase accordingly. However, this increase in current increases the generation of heat of the charging circuit and discharge circuit. For example, Japanese Patent Laid-Open No. 2010-30284 has disclosed a method of restricting currents by performing charging and discharge via a resistor.
Unfortunately, the cost of the charging circuit and discharge circuit disclosed in Japanese Patent Laid-Open No. 2010-30284 can be reduced because current restriction using the resistor need only be performed, but this arrangement does not shorten the charging time and discharge time.